A device used with a diagnostic or therapeutic x-ray system consisting of single/compound metal composition sheets that are designed to be placed in the path of the x-ray beam before it reaches the patient (target). It is typically made of aluminium, copper, tin or a combinations of these. Diagnostic and therapeutic x-ray systems typically have a designated slot located in the x-ray tube assembly where it can be inserted and interchanged. In diagnostic x-ray the filter removes low energy radiation before reaching the patient to protect from useless radiation. In therapeutic applications, it reduces low-energy photons delivered to the patient managing beam quality and adequate irradiation.